[PATCH v10 00/21] Support ext4 on NV-DIMMs

[Matthew Wilcox]

One of the primary uses for NV-DIMMs is to expose them as a block device
and use a filesystem to store files on the NV-DIMM.  While that works,
it currently wastes memory and CPU time buffering the files in the page
cache.  We have support in ext2 for bypassing the page cache, but it
has some races which are unfixable in the current design.  This series
of patches rewrite the underlying support, and add support for direct
access to ext4.

Note that patch 6/21 has been included in
https://git.kernel.org/cgit/linux/kernel/git/viro/vfs.git/log/?h=for-next-candidate

This iteration of the patchset rebases to 3.17-rc2, changes the page fault
locking, fixes a couple of bugs and makes a few other minor changes.

 - Move the calculation of the maximum size available at the requested
   location from the ->direct_access implementations to bdev_direct_access()
 - Fix a comment typo (Ross Zwisler)
 - Check that the requested length is positive in bdev_direct_access().  If
   it is not, assume that it's an errno, and just return it.
 - Fix some whitespace issues flagged by checkpatch
 - Added the Acked-by responses from Kirill that I forget in the last round
 - Added myself to MAINTAINERS for DAX
 - Fixed compilation with !CONFIG_DAX (Vishal Verma)
 - Revert the locking in the page fault handler back to an earlier version.
   If we hit the race that we were trying to protect against, we will leave
   blocks allocated past the end of the file.  They will be removed on file
   removal, the next truncate, or fsck.


Matthew Wilcox (20):
  axonram: Fix bug in direct_access
  Change direct_access calling convention
  Fix XIP fault vs truncate race
  Allow page fault handlers to perform the COW
  Introduce IS_DAX(inode)
  Add copy_to_iter(), copy_from_iter() and iov_iter_zero()
  Replace XIP read and write with DAX I/O
  Replace ext2_clear_xip_target with dax_clear_blocks
  Replace the XIP page fault handler with the DAX page fault handler
  Replace xip_truncate_page with dax_truncate_page
  Replace XIP documentation with DAX documentation
  Remove get_xip_mem
  ext2: Remove ext2_xip_verify_sb()
  ext2: Remove ext2_use_xip
  ext2: Remove xip.c and xip.h
  Remove CONFIG_EXT2_FS_XIP and rename CONFIG_FS_XIP to CONFIG_FS_DAX
  ext2: Remove ext2_aops_xip
  Get rid of most mentions of XIP in ext2
  xip: Add xip_zero_page_range
  brd: Rename XIP to DAX

Ross Zwisler (1):
  ext4: Add DAX functionality

 Documentation/filesystems/Locking  |   3 -
 Documentation/filesystems/dax.txt  |  91 +++++++
 Documentation/filesystems/ext4.txt |   2 +
 Documentation/filesystems/xip.txt  |  68 -----
 MAINTAINERS                        |   6 +
 arch/powerpc/sysdev/axonram.c      |  19 +-
 drivers/block/Kconfig              |  13 +-
 drivers/block/brd.c                |  26 +-
 drivers/s390/block/dcssblk.c       |  21 +-
 fs/Kconfig                         |  21 +-
 fs/Makefile                        |   1 +
 fs/block_dev.c                     |  40 +++
 fs/dax.c                           | 497 +++++++++++++++++++++++++++++++++++++
 fs/exofs/inode.c                   |   1 -
 fs/ext2/Kconfig                    |  11 -
 fs/ext2/Makefile                   |   1 -
 fs/ext2/ext2.h                     |  10 +-
 fs/ext2/file.c                     |  45 +++-
 fs/ext2/inode.c                    |  38 +--
 fs/ext2/namei.c                    |  13 +-
 fs/ext2/super.c                    |  53 ++--
 fs/ext2/xip.c                      |  91 -------
 fs/ext2/xip.h                      |  26 --
 fs/ext4/ext4.h                     |   6 +
 fs/ext4/file.c                     |  49 +++-
 fs/ext4/indirect.c                 |  18 +-
 fs/ext4/inode.c                    |  51 ++--
 fs/ext4/namei.c                    |  10 +-
 fs/ext4/super.c                    |  39 ++-
 fs/open.c                          |   5 +-
 include/linux/blkdev.h             |   6 +-
 include/linux/fs.h                 |  49 +++-
 include/linux/mm.h                 |   1 +
 include/linux/uio.h                |   3 +
 mm/Makefile                        |   1 -
 mm/fadvise.c                       |   6 +-
 mm/filemap.c                       |   6 +-
 mm/filemap_xip.c                   | 483 -----------------------------------
 mm/iov_iter.c                      | 237 ++++++++++++++++--
 mm/madvise.c                       |   2 +-
 mm/memory.c                        |  33 ++-
 41 files changed, 1229 insertions(+), 873 deletions(-)
 create mode 100644 Documentation/filesystems/dax.txt
 delete mode 100644 Documentation/filesystems/xip.txt
 create mode 100644 fs/dax.c
 delete mode 100644 fs/ext2/xip.c
 delete mode 100644 fs/ext2/xip.h
 delete mode 100644 mm/filemap_xip.c

-- 
2.0.0

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